This invention relates to portable powered sanders or other similar abrading tools in which an abrading shoe is driven for straight line reciprocating movement relative to a carrying body.
In my U.S. Pat. No. 3,932,963, I have shown a straight line abrading tool in which the reciprocating shoe of the device is driven by a piston structure through a pair of gear units, in a manner effectively balancing out lateral forces exerted by the gear drive assembly. The piston structure desirably is of a type having two piston heads at opposite ends thereof, with the gear units preferably engaging toothed racks formed on opposite sides of the piston structure at a location between the two piston heads. Lower portions of the gear units in the device of that prior patent engage two racks formed on the shoe to reciprocate the shoe oppositely from the piston.